Modeling the lifespan of OLED (Organic Light-Emitting Diode) is a complex task: different factors may impact the lifespan, with possible interactions between them. However, the literature on this subject is still scant. This work proposes new parametric models for the OLED lifespan. For cost and accuracy reasons, the Design of Experiment (DoE) methodology is used for the estimation of model parameters. Different models are computed from thermal and electrical experimental aging tests. These innovative models involve, simultaneously, the current density, the temperature and their interactions, which are rarely taken into account in aging studies. The analysis of the model parameters highlights the prevalence of temperature compared to current density on the OLED luminance performance.